Originally Posted by

**iknowone** $\displaystyle

3) 1-16a^4

$

Is an example of the difference of 2-squares which obeys: $\displaystyle a^2-b^2 = (a-b)(a+b)$

*But that's to the power of 4, which is why I don't get it.*

$\displaystyle

2) 2ab^3-2ab

$

Is an example of the greatest common factor and then difference of squares: $\displaystyle 2ab(b^2-1) = 2ab(b+1)(b-1)$

*Huh?? =(*

$\displaystyle

17) a(x-a)+b(a-x)-c(x-a)

$

Observe that $\displaystyle (a-x) = -(x-a)$. Do you know the various methods for factoring and what it means to be completely factored?

*Nope...*